This invention relates to a distributor type fuel injection pump for use with a fuel-injection engine, and more particularly to a fuel injection pump of this type which is adapted for partial cylinder operation of the engine.
In recent years, to cope with increased fuel cost, it has been proposed and actually practiced to carry out a partial cylinder operation of a diesel engine where fuel is injected into only part of the cylinders of the engine, during low load operation of the engine such as running on a downward slope. For example, to carry out such partial cylinder operation, an in-line type fuel injection pump is provided with a solenoid valve arranged to close one of fuel feeding lines leading to a plurality of plunger pumps of the injection pump to thereby interrupt feeding of fuel to part of the plunger pumps. However, this arrangement cannot be directly applied to a distributor type fuel injection pump which is adapted to feed fuel to all of a plurality of cylinders of an engine through a single plunger pump, as distinct from an in-line type fuel injection pump which is adapted to feed fuel to the engine cylinders through as many respective plunger pumps.
However, while distributor type fuel injection pumps have been widely used in small-sized and medium-sized automotive vehicles, there is an increasing request for saving of the fuel cost for automobile engines. Therefore, strongly desired is the appearance of a distributor type fuel injection pump which enables carrying out a partial cylinder operation of an engine associated therewith.